Explain why most homes have parallel circuits rather than series circuits?

For any electrical appliance (lamps, washing machines, etc.) to operate at their rated power, they must be subject to their rated voltage. This is why both values are shown on their 'nameplates' -e.g. for a lamp: '60 W / 230 V', etc.

As each branch of a parallel circuit is subject to the same (supply) voltage, by connecting all the appliances in a home in parallel with the supply, each appliance will also be subject to their rated voltage. This is the primary reason for connecting appliances in parallel.

A secondary reason is that, if appliances were to be connected in series, and one appliance stops working, then it will disconnect all the other appliances in the home!